Our primary objective is to investigate the natural histories of herpesvirus infections (Herpesvirus hominis, Ebstein Barr Virus, Cytomegalovirues, and Varicella Zoster) in human populations which are at high risk for cancer development and conduct molecular and animal studies aimed at determining the oncogenic potential of certain of the fresh isolates. The study population will include renal transplant recipients, young women with herpetic cervical infections, especially those caused by cytomegalovirus (CMV), and infants and young children with chronic CMV infection. In the natural history studies, longitudinal, virologic, serologic, and clinical parameters will be assessed in order to gain an overview of the infectious background upon which cancers may develop in later life. The major factors to be examined include: relative incidence, clinical nature, persistence, recurrence rates, coexistence of infection, virulence, and reactivation factors. Definition of the differential serologic responses, assayed by indirect fluorescent antibody methods with "early", "late", nuclear and membrane antigens of all the herpesviruses, will be given particular attention in all three study groups. Molecular studies will include: the relative role of the herpesviruses in white blood cell transformations and determinations of the serologic and biologic characteristics of genital and nongenital strains of CMV. The tumor producing capacity of transformed white blood cells and the transforming agents harbored by them, as well as certain of the lytic isolates, will be assessed in marmosets and newborn hamsters.